1. Field of the Invention
This invention relates to an electronically controlled suspension system that is adapted to adjust car height more quickly after the engine of a car has been started than while the car is in an ordinary stationary condition by shortening the time during which the mean value of car height is calculated only once after the engine key switch controlling the startup of the engine has been turned on.
2. Description of the Prior Art
Various types of electronically controlled suspension systems have been developed that permit adjusting the car height to provide comfortable ride and stable driving. This type of suspension system generally decides within a given time when to start the car height adjustment, computing the mean car height to be compared with a reference car height. Setting is made to give a longer time (such as 30 seconds) for said given time, herein referred to as a "car height judgement time", while the car is running in order that the car height should not be adjusted every time the car runs on road surface irregularities or every time the car position changes temporarily as a result of acceleration and deceleration. A shorter "car height judgement time" is given when the car is stationary so that changes in car height induced by the riding or alighting of a person or persons are made up for rapidly. Namely, the "car height judgement time" is shorter when the car is stationary than while it is running. But if the "car height judgement time" is cut too short, short car height adjustment may begin while a person or persons are riding or alighting, thereby giving an uncomfortable feeling or sensation to such person. The preferable time should therefore be long enough to allow the driver and all of the passengers to fully get in or out of the car (such as 6 seconds).
When the driver and passengers, if any, have gotten into the car, the car height adjustment should preferably begin as soon as possible. With the conventional electronically controlled suspension systems, however, car height adjustment does not begin until the given "car height judgement time" (such as 6 seconds), though the duration is shorter than the "car height judgement time" allowed while the car is travelling, has passed even if the engine key switch is turned on.